What sensor triggers the radiator fan?
Short Answer
The radiator fan is usually triggered by coolant-temperature input, but many machines also consider refrigerant pressure, hydraulic oil temperature, intake-air temperature, or engine-controller logic. The exact trigger depends on the machine design, so the sensor signal and the fan-control module should be checked together before replacing the fan motor or controller.
What To Check
- Confirm which temperature or pressure sensor the machine uses for fan command on that model.
- Check live sensor values, wiring continuity, and whether the fan controller is receiving the expected signal.
- Verify the controller or sensor part number against the machine serial and old label before ordering.
Related JIAJUE Parts
Send the machine model, serial number, old part label, connector photos, and fault details before ordering so JIAJUE PARTS can help reduce wrong fitment.
Source Record
This question was selected from Google People Also Ask results for the keyword 637-6650 fan controller excavator problem. The answer is rewritten from JIAJUE parts-matching and sourcing practice, not copied from Google or any source page.
